package 路径问题;

import java.util.Scanner;

public class test6 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int m = in.nextInt();
        int n = in.nextInt();
        int[][] nums  = new int[m][n];
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                nums[i][j] = in.nextInt();
            }
        }
        System.out.println(calculateMinimumHP(nums));
    }
    public static int calculateMinimumHP(int[][] dungeon) {
        int m = dungeon.length;
        int n = dungeon[0].length;
        int[][] dp = new int[m+1][n+1];

        for (int i = 0; i <= m; i++) {
            dp[i][n] = Integer.MAX_VALUE;
        }
        for (int j = 0; j <= n; j++) {
            dp[m][j] = Integer.MAX_VALUE;
        }
        dp[m][n-1] = dp[m-1][n] = 1;

        for (int i = m-1; i >= 0; i--) {
            for (int j = n-1; j >= 0 ; j--) {
                dp[i][j] = Math.min(dp[i][j+1],dp[i+1][j])-dungeon[i][j];
                dp[i][j] = Math.max(1,dp[i][j]);
            }
        }
        return dp[0][0];
    }
}
